Beta testing the new BHK Preamp

Audio Components Amplifiers
101
wglenn said I must say that Paul is indeed correct when he says that a good preamp adds something valuable to the sound. . . .

These things that I am hearing are not subtle.

Elk, buy one.


:slight_smile:

I am very tempted. I recognized long ago that the preamp is critically important and I have found the preamp often has a bigger impact than the amp. The BHK has the additional benefit of a suberp headphone amp.

A fabulous review, well stated.

I am eager to read your report of Galen’s reactions. He has good ears and does not mince words.

102

Thanks for the kind words, guys. This was just a first blush but I obviously am taken by the way this thing sounds in my system.circle-of-hearts-smiley-emoticon_gif

103
Don't get me wrong, the BHK 250 is considerably better than the NCore and I have no criticisms of the new power amp. I am just expressing that I was satisfied with the 250, thrilled with the BHK Preamp.
I'm still kind of preparing my next follow up comments as the Pre burns in, but i just wanted to echo this sentiment. The BHK signature amps are wonderful amplifiers, but for whatever magical reason, the pre in combination with the BHK amps is an absolute masterpiece. To say that they work well with each other would be a gross understatement. I would tell anyone that is considering the BHK amplifiers that it's a must that they get the preamplifier to fully realize the potential of those amplifiers.

I would also add that burning in, the pre continues to get better and better. I’ll hold off anything further though for a couple more days… :slight_smile:

104

Have you been able to compare it with another amp ?

105

“I would also add that burning in, the pre continues to get better and better.” - pp

Wow. I may have to call in sick tomorrow.4_gif

106
rogerdn said

Have you been able to compare it with another amp ?


That’s the next step, hopefully in the next day or so, to hook the ARC Ref 610’s back up to the Pre and A/B, but honestly i’ve been enjoying this combination so much that i haven’t wanted to touch…anything. (not to mention that it’s been 118 here in the Phoenix area, and i’d just assume not turn on those beasts lol)

  Wow. I may have to call in sick tomorrow.<img class="spSmiley" title="4_gif" alt="4_gif" src="http://www.psaudio.com/wp-content/forum-smileys/4.gif" /> -wglenn

I’m lucky that my listening room and office are one and the same. And i can sit down in my listening chair and write patent applications while i enjoy this product :slight_smile: Very lucky this week!

107

Hello lucky beta testers… If you all don’t mind,could you kindly list the brand name and model number of any preamps owned that are being used in comparison to the BHK pre in your reporting? It would give a great baseline to work from for anyone interested in a BHK future purchase.

Thank you very much…77_gif

108

Firstly, the Preamp is a major audio step up from my Conrad Johnson Premier 17LS preamp (circa 2002). It never ceases to amaze what sound there is on a CD and how the DSD, the BHK250 and now the BHK Preamp progressively add to the sound. Things are there that I’ve never heard before despite 40 years of listening. I want to burn the unit in before adding any additional comments on just how good it is - the BHK250 took me a couple of weeks to burn in and cease lamenting the absence of my Conrad Johnson 620 amp with its 11 tubes that heated the house in summer.

Couple of points on the BHK preamp - firstly I echo the comments of previous beta tests who noted that the standby illumination varied between the various PS units (the BHK amp and preamp are about an 8 on a 1 to 10 scale, the DSD about a 6 and the PWT, the PS power base and the PS5 around 4. On the same scale of brightness, the BHK preamp display is about a 20. Secondly the mono button on the remote appears to do precisely nothing (either through the amp or the phones), while the preamp volume button for some reason also switches on the display on my PS5 for about 20s.

Working on getting used to the headphones via the BHK Preamp output. I ran my Sennheiser 800s via a Ray Samuels Raptor headphone amp and was very pleased - the sensitivity of the phones/headphone output requires I use an output of about 80 on the BHK for the phones whereas 64 is fine on the BHK 250 amp. Would be nice if the two volume settings were closer to one another.

More later

Mike W.

109

Mike, thank you for posting. I too have owned a Premier 17LS for over a decade and always thought it was a great preamp—particularly with the right tubes. But it’s getting a bit long in the tooth, perhaps. So I will be very interested in your opinions after some more break-in on the BHK.

110

Just another minor update…I’ve been waiting on a couple of XLR splitters to connect up my two Revel Ultima Rhythm2 subwoofers-those arrived this afternoon. I seem to recall a post from Paul in another thread where he mentioned that it was possible to use an XLR splitter in the output stage without signal degradation-in any event, that’s what seems to be the case-XLR’s now going to the two 300’s and two subs without any issue. The subs are now present and accounted for. A very nice development so i thought i would report. :slight_smile:

111

Just wondering what fuse comes with the preamp? Has anyone compared the preamp with stock fuse to a synergistic research or hifi tuning fuse?

Apologies if this has been answered already.

112
billg said Just wondering what fuse comes with the preamp? Has anyone compared the preamp with stock fuse to a synergistic research or hifi tuning fuse?

Apologies if this has been answered already.


And while we are taking about the fuse can someone give the specs for it , I figured while I am saving for my Pre Amp I would get started and buy the fuse for it .

magicknow

113

The 120V version will use a 2A 5x20mm. The 230V version will use a 1.6A 5x20mm

114

I will be getting my Pre-Amp tomorrow. I am currently using the Coincident Statement Line Stage with upgraded tubes from Psvane. Naturally I am on-call this weekend and may not get much chance to listen to it until Monday. At least I will get the benefit of the weekend for burn in.

As well, my mono-blocks will be back from repair on Tuesday. One of them decided to stop working several weeks ago. Apparently the smaller transformer overheated then burned out. Both got sent in to get looked over and updated to the current specs. As usual, I have been impressed with the customer service side of PS Audio.

I dragged an old amp out of the basement to use now; the Apt 1-a 36 year old solid state amp from my medical school days. Once I am back up and running the mono blocks with the new pre-amp I can start to do some serious listening.

Alan

115

Should be an interesting comparison with the CSLS.

116

One of the musicians ( Bluegrass - band is Notch 9) stopped by last night just after I got the turntable reset from the move. He had been over a few days before to listen to Torreys. His first reaction to the new BHK preamp was “everything’s clearer!!!”. We listened to Dusty’s “Son of a Preacher Man” and he was amazed at the improvement to the clarity of the tone.

Now I put Dusty on the turntable. The equipment path is now Miyajima Kansui on VPI Classic 3 to ARC SP-10 to BHK preamp and Mono’s to Maggie 20.7. This was Jaw Dropping sound. Never has the turntable sounded better. The BHK preamp makes the phono of the SP-10 sound so much better than SP-10 straight into the BHK mono’s. How can all that more stuff in the path sound so good?

The sound of the RBCD’s through the BHK was so improved I finally thought I was hearing digital as it should be. I never expected the BHK to improve the sound of a '83 SP-10 so much playing records. I wrote earlier that for RBCD’s the SP-10 was now a vintage piece to the BHK and it is, but the phono of the SP-10 is still pretty good at sounding better than RBCD (probably all the record distortion I like) and I did not expect that at all. The future BHK Phono has a real challenge ahead. I bet it wins!, based on the preamp’s incredible sound!

The musician is mighty impressed with how real the sound of people singing is. He said this is just like when he plays with friends at home in the living room.

117

My BHK preamp finally arrived on Friday. Looks like there might have been some updates - I noticed a tube timer in the setup menu. I let the unit run in for the afternoon before giving it a once over at night.

My comments:

Functional issues -

  1. when using an input as an HT bypass - when I select the HT input from a previous input, the output level remains at the previously selected input’s level until the volume up/down button is pressed. When going to another input from the HT input, the level also remains at the HT level until the volume up/down button is pressed. Going to the HT input might not be to bad, but going to another input could result in full output until the volume button is pressed.

  2. the HT bypass is not a true bypass - i.e. input is not passed directly to the output. It is more a fixed output input where the output level is fixed. This is mostly a good thing - it allows one to adjust the levels to better match other components, and takes advantage of having a preamp in the chain (more about this later).

  3. the transport buttons on the remote are swapped. The “>>|” button is fast forward, and the “>” button is skip to the next track (when used with the PW Transport). Generally, “>>|” is the skip to the next track, and that is what happens with the old remote that came with the PW Transport.

  4. I had one instance where turning off the preamp did not turn off the BHK 250 amp using the trigger output - but I have not been able to replicate the issue.

  5. Speaking of the tube timer - there was no mention of the expected tube life in the manual (or the timer of course).

Listening -

The comments made by others are spot on. The improvement in sound going from connecting the DirectStream directly to the BHK amp is nothing short of a revelation. Those of you who were less than satisfied with Torreys Final may find that putting the BHK preamp in the chain will resolve most of your concerns (albeit at a substantial cost of course - free for the DAC software versus the cost of the BHK preamp). It really allows you to hear all the advantages of Torreys - lack of jitter resulting in greater focus of instruments, with the BHK preamp bringing the sound to life in terms of both scale and bloom. This combination really gives a phono system a run for its money (and I have never experienced that before). I am becoming convinced that reducing jitter might just be the holy grail for improving digital and making it compete with analog.

As mentioned above, having a preamp between the DAC and amp brings about a substantial improvement. It’s as if the signal coming from the DAC is running on full RPM, with no extra head room to spare. With the preamp in the chain, the strain is just gone - replaced by an effortlessness as if the system is now running at mid RPM’s with plenty of juice to spare (I believe this is what Paul and others have been saying all along - it’s just hard to understand until one hears the improvement).

That’s it for now, I will respond again once I have let the unit break in some more (or if I find any other bugs).

Now keep in mind these comments were made without substantial break in - if things get even better, I can’t wait.

118
bad wolf said My BHK preamp finally arrived on Friday. Looks like there might have been some updates - I noticed a tube timer in the setup menu. I let the unit run in for the afternoon before giving it a once over at night.

My comments:

  1. Speaking of the tube timer - there was no mention of the expected tube life in the manual (or the timer of course).
?!?!?!? Really? It was implemented that quickly? I don't know what to be stunned more about: 1) Paul actually implemented a suggestion I made or 2) it happened so fast . . .

Get the crash cart. (Charge to 1000! Clear!)

But yes, it needs to be mentioned in the manual.

I don’t know about the tubes in the BHK, but the tubes in my AR LS-26 are recommended to be changed every 4000 hours. Those are for 6H30 tubes, however, which do have a long life.

119

I initially focused on the headphone amp of the new BHK preamp. My comparisons have been done using my existing headphone amp, a Grace M-902, and the following headphones: Audeze LCD-2, Grado RS-1, and Shure SE846.

I had purchased the Grace M-902 over 11 years ago because it had the following features:

  • Remote volume control
  • Multiple inputs
  • Balance control
  • High quality DAC with up to 24/192 resolution
  • Sufficient power to drive most headphones
  • Good sound
Since that time other changes in my system have rendered most of those features unnecessary. My PS Audio DirectStream DAC, for instance, can provide the balance and remote volume control as well as providing access to most of the sources in my system and is a far better DAC than the Grace.

Like the DS, the BHK preamp also provides balance and remote volume control as well as access to ALL of the sources in my system through a very easy to use front panel and remote. It also has what turns out to be a very good headphone amp.

As far as functions go, I’ve found the remote input selector, volume control, and balance all very comfortable and intuitive. The remote is well laid-out and easy to use in a darkened room. The remote pickup seems to be responsive from a wide range of angles and is a great improvement over the pickups in my PS Audio PWT, my kit-built DS, and my old GCC-250.

I first compared the headphone amp in the Grace to the BHK using the Audeze LCD-2s, which are large, open-backed, power-hungry ‘phones. My source was the analog output from my Oppo BDP-83SE and a variety of SACDs. This revealed that the Grace sounds somewhat thin and has a narrower soundstage compared to the BHK. I should note that I ran the Grace in both its high-gain and low-gain modes (finding, as expected, that the high-gain mode yielded better results with the LCD-2s). While the sound of the Grace was still very enjoyable, the BHK grasped the Audeze ‘phones with an authoritative hold and provided a much richer mid- and low-range sound.

The Grado RS-1s, while still greatly lacking in the bass department, gained a similar enhancement when driven by the BHK.

The Shure SE846s results were less satisfying. The ‘846s are very efficient IEMs and will perform very well with the smallest of amps. Letting the BHK drive them is sort of like putting a ½ gallon-per-hour drip emitter for your garden at the end of a firehose – that emitter will still drip, but can you really say it drips more authoritatively?

Anyway, there was significantly less difference in the sound produced by the Shures when driven by the two amps than for the Audeze or Grado phones, though the BHK still provided better imaging and richer lows and mids. What was much more noticeable was the level of background noise. While the Grace hasn’t a trace of background noise until the volume is turned up well past reasonable listening levels, the Shures revealed that the BHK has a constant background hiss that sounds like a fan is running in the corner of your listening room. This hiss does not change with volume or source – it is as loud when the volume is set to ‘1’ as it is when the volume level is at ’60.’ The only change is that it becomes slightly louder in one channel between approximately ‘40’ and ’50.’ The hiss, while not particularly distracting during energetic sections of a song, draws more attention to itself during quiet passages and between songs. It also obscures some subtle, higher-frequency details. Additionally, the ticking sound of the volume control is more noticeable with the Shures (and more resonate, too – some of the ticks sound like a fingernail clicking against a partially filled water glass).

While I most often use the LCD-2s when listening to ‘phones on my home system, I do use the Shures when I want to eliminate background noise. I also use them when comparing or editing recordings as they don’t hide any details. I’m not sure that the level of noise in the BHK will allow me to do this. While this isn’t a deal breaker for me, it also means I probably won’t be letting go of the Grace in the near future.

Will the hiss be audible with your headphones? Maybe not. When I went back to the LCD-2s and listened for specifically for the hiss, I really still couldn’t hear it – just an immersive, rich, captivating sound. Even if the hiss is audible, it’s possible that different tubes or adjustments to the input gain may help to reduce it.

-Pb

120

As with the headphone amp testing, my comparisons of the preamp used my Oppo BDP-83SE as the sole source. When switching between preamps, I used the same interconnects and same output jacks on the Oppo. The power amplifier for all testing was a McCormack DNA-0.5 and the speakers were a pair of Quad ESL-988s backed with an ancient Sunfire Signature sub. Interconnects and speaker cables are PS Audio Transcendent.

Comparing the BHK to the Grace M-902 preamp showed that the Grace’s preamp has much of the same sonic signature as its headphone amp – thin, somewhat brittle sound with a very narrow soundstage. Changing the channel cross-feed setting on the unit had little impact on this.

In contrast to the Grace, the BHK had a much wider soundstage and a much better balanced sound with a rich low- to mid-range and was greatly preferable.

When compared to my McCormack TLC-1 preamp, the differences between the two units were much smaller. Playing “Cause We’ve Ended as Lovers” from the excellent Analogue Productions SACD reissue of Jeff Beck’s “Blow by Blow,” the TLC-1’s soundstage approached the width and depth of the BHK and the bass response (using the buffered outputs on the TLC-1), while not as robust, was very good. Where the TLC-1 really failed in comparison to the BHK was that it created a somewhat box-like sound that made it sound as though Jeff was playing his guitar in a tiny room while the rest of the band played outside. The BHK brought him back into the room with the other musicians and gave his guitar substantially more body. On other recordings the TLC-1 never sounded bad, but it also hid a layer of dimension and realism in the recording that the BHK was able to reveal, and that revelation brought life into the room and drew me into music.

-Pb